Thermostat switch



O.G.MYERS THERMOSTAT SWITCH Sept. 20, 1927. 1,642,742

Filed Oct. 1, 1924 PatentedSep t. 20, 1927. V

UNITED I ES PATENT a PP Application filed October 1, 1924. Serial No. 740,945.

This invention relates. to electrically exterior shell 2 is a pair of resistance heatheated devices, such asovens, irons, etc., and ingelements B and O of any suitable conespecially to a thermostatically actuated struction, said elements being generally inswitch whereby the temperature of such dedicated by annular ribbons helically 5 vices may be automatically regulated; O wound about .the inner container as shown The object of the present invention is to in Fig.1.

generally improve and sim lify' the con- The purpose of the present invention is struction and operation 0i thermostatic to provide-a sim le, sensitive thermostatic switches whereby electric circuits are con switch whereby t e electric circuit through 0 trolled; to provide a switch which is ad-- the resistance elements may be automatijustable for different temperatures; a switch cally controlled, so" that a predetermined which is exceedingly sensitive in action and temperature may be maintained within the which is capable of automatically making cooking utensil. Another purpose of the or breaking a circuit within temperature invention is to provide an adjustable ther- 1 variations of 1 R; and furthermore, to mostatic switch whereby dilferent temperaprovide a thermostat switch consisting of turcs maybe maintained and automatically two. members having different degrees "of maintained when the switch is adjust-ed. expansion and one member forming a part- In the present instance the cooking uten- J of the device to be heated. sil indicated at 3 forms one member of the One" form which 'my invention may: asswitch and a rod 6 the other member. The sum is-exemplified in the following descripcooking utensil is constructed of aluminum, tion andillustrated in the accompanying while the rod 6 is constructed of a metal drawings, in whichknown as invar. This met-a1 has a V6 Fig. l is a side elevation of an electric low coefficient of expansion when compar1-. 75

cooker showing the application of the thenson is made with aluminum, and it is theremostatic switch, said side elevation being fore ideal for the purpose sought. To obpartially in section and partially broken tain the full expansion of the cooking utenaway. x sil 3, a pair of side lugs is employed. These Fig. 2 is a bottom view of the electric lugs are indicated at 7 and 8 and they are 0 cooker, said viewalsoshowing the thermo welded or otherwise secured to the exterior static switch. V surface of the cylindrical container. The

Fig. 3 is a detailed side elevation .of a porlug 8 is extended downwardly a suitable distion of the base showing the slot through t'anc'e to receive one end of the rod 6. The which the temperature.regulating lever'exother lug 7 is also extended downwardly be- 5 '-tends. low the container and is bent at right angles Referring to the drawings in detail, and to form a bearing bracket 9, the ur ose of particularly to Figs. 1 and 2, A indicates an which will herelnafter be describe The enlarged base-inemberupon which is mount-' lugs 7 and 8, as previously stated, are directed an exterior cylindrical shell 2, said'shell 1y welded to the container 3,'and it will also 00 40 being suitably secured to the base A or be noted that they are surrounded by the formed integraltherewith as shown in Fig. resistance or heating element C. The por- 1. Supported or hung from the upper end tion of the cooking utensil to which the lu s of the shell by means of an annular lip-like 7 and 8 are secured is for this reason su extension, and extending downwardly into iected to the greatest temperature-and will 05 4 the shell, is a cylindrical container 3 also be subjected to a, maximum amount of which serves as a receptacle for material to expansion, and it is for this reason that the be cooked. 'This cylindrical container is lower ends of the lugs are bent slightly outsmaller in diameter than the exterior shell wardly as indicated at 10 to maintain them ,1?

2 and an intermediate annular space 4 (is out of contact with that portion of the uten thus formed, Disposed in this space and insil which is not subjected to the same temsulated both from the container 3 and the perature; that is, the utensil, at points V slightly below or above the heating element C, will be cooler than that portion directly A underlying the heating element, and as such temperature variations exist throughout the container or utensil, it obvious that the lugs should not contact except with that portion which is subjected to the maximum amount of expansion.

The switch opening and closing the circuits through the heating elements B and C is best illustrated in Fig. 2. It consists oftwo levelsgenerally indicated at D and E. The lever D is provided .with an adjustable contact 12 atone end, and its opposite end is bent at right anglesor offset as in-' function of a link to impart a swinging I being formed movement to the lever be later described.

D. .This action Wlll The lever E in reality carries the switch.

It'is pivotally'supported on a bracket 1'? at the point indicated at- 18.. lit carries a pair of contacts 19 and 2d, the contact 20 on a spring arm 21 which is securedto lever E at the point 22. @ne side of the electric circuit is connected with the contact 19 through a wire 2?, and the other side of the circuit is connected with a contact 24 through a wire 25. Contact 20 is moved to and away from the contact 19 by means of the lever D and the adjustable contact 12 and the circuit is in this manner automati cally opened and closed. Wires 2? and 25 are connected with an ordinary socket, such as shown at 26, and an ordinary plug switch is inserted when it-is desired to employthe cooker; that is, the heating elements employed in connection with the cooker shown require a com aratively small wattage and it is thus possible to use the ordinary lighting circuit. A tell-tale light is employe as indicated at 27. This light is shunted in on the circuit and thus visibly indicates when the circuit goes on and ofi The cooker is capable of operating at difi'erent temperatures and it is tor this reason that an adjustable switch is employed, adjustability being obtained by theswinging actlonof the switch lever E.

To clearly understand this action it will be supposed that lever D assumes the 'full line position shown in is cold. It lever E assumes the full line position, the lowest temperature will be bbtained. as lever D will only have to travel and 29. If

and as it is free to Fig.2 when the device r the distance formed between thepoints 28 lever E is swung in the direction of arrow a, it will be seen that the distance between the points 28 and 29 will be, increased and that the temperature finally obtained will be correspondingly increased. The highest'temperature obtainable will be obtained when lever E has been moved its maximum distance, or has reached the end of "its guide slot, which is indicated at 30. (See Fig; 3.) Notches are formed in the bottom of the slot 30 as shown at 31 and the lever E may one of these notches. a predetermined temperature and the switch maythus be set to any predetermined temperature desired.

The operation of the switch will be as follows; When an electric circuit is closed through the heating elements B and C, throughinsertion of an ordinary switch plug in the socket 26, the inner'container 3 will gradually become heated and' will finally reach a predetermined, temperature. The utensil will, of course, also gradually expand in proportion to the temperature increase expand equally in all directions, itis-obvious that lug 7 will move outwardly from a given central point, and similarly that lug 8 will move outwardly a given distance from a central point within the utensil. Again, the, exterior diameter of the utensil 3 is increased due to expansion of the metal and hence the distance between the lugs 7 and 8,

it might be stated that not expand but retains its original length,

as the metal from which it is constructed is, practically speaking, non-expansible. end of the rod'6 is secured to the lug 8 and the other end is secured to the" lever 1). Hence, as the distance between the lugs 7 and. 8 increases,-a pull will be exerted by rod 6 through means of in 16 on lever D an it will swing inward y in the direction of arrow 7) towards the spring One a no

lever 21 and the circuit will be broken through the contacts 19 v engages the spring and 20 when set screw 12 Such arm and imparts movement thereto;

d breaking of the circuit, is accomplished when a predetermined temperature is reached and this predetermined temperature will, of course, depend upon the position assumed by the switch lever E as previously described. The moment the circuit is broken. through-the elements B and C, the temperature gradually drops and reverse movement is transmitted to lever D, thus permitting the contacts 19 and 20 to again engage. ,The circuit is, as the result, intermittently bpened and broken and the predetermined temperature desired is thus auto- -matically maintained.

The thermostatic switch here shown perweaves 1 members forms the cooking utensil itself,

and it is also due to'the fact that the only movable member actuated by thermostatic action is the lever D, and as only one movable member is employed lost motion may be practically eliminated and close regulation can be obtained.

While certain features of the present invention are more or less specifically illustrated, I wish it understood that various changes in form and proportion may be resorted to within the scope'oi'" the appended claims, I similarly wish it understood that the materials and finish of the several parts employed may be such as the experience and judgment of the manufacturer may dictate or various uses may demand.

Having thus described my invention, what 1 claim and desire to secure by Letters Patent is v l. A. device of the character described comprising a cylindrical-shaped container constructed of an expansible metal, a air of lugs secured to the container at points diametrically opposite each other, a lever pivotally. mounted on one of said lugs, a rod of invar metal secured at one end to the opposite lug and at the other end to the pivotally mounted lever at a point adjacent the pivot so as to transmit a rocking movement to the lever during expanding action of the cylindrical container, a second pivotally mounted lever, a switch carried thereby and adapted to control an electric circuit,

' and a projecting arm on the switch in the pathiof movement of the first-named lever,

' said projection adapted to open and vclose the switch when engaged and released by the first-named lever. l

2. A'device of the character described comprising a cylindrical-shaped container constructed of an expansible metal, a pairof lugs secured to the container at points diametrically opposite each other, a lever piv- I otally mounted'on o'neot said lugs, a rod or invar metal secured at one end to the opposite lug and at'the other end to the pivotally mounted lever at a point adjacent the pivot so as to transmit a rocking movement to the lever during expanding action of the cylindrical container, a "second 'pivotally mounted lever, a switch carried thereby and adapted to control anelectric circuit, a projecting arm on the switch in the path of movementof the first-named lever, said projection adapted to open and close the switch when engaged and released by the firstnamed lever, and, means permittingadjust; ment of-the position of the lever upon which the switch is mounted.

3. A device of the character described comprising a container constructed of an exlug and at the other end to the pivotally I mounted lever at a point adjacent the. pivot so as to-transmit a rocking movement of the lever during the expanding action of the container, a second pivotally mounted lever, a switch carried thereby and adapted to control the electric circuit and means on the switch disposed in the path of movement of thefirst-named lever, said means adapted to open and close the switch when engaged or released bythe first-named lever.

At; A device of the character described comprising a container constructed of an expansible material, 'a members secured to the container atpoints opposite each other, a lever pivotally mounted on one of said lugs, a rod of non-expan sible material secured at one end to the o posite liig and at the-other end to the pivotally mcunted lever at a point adjacent the pivot so as to transmit a rocking movement of the lever during. the expanding action of ther container, a second pivotally mounted lever, a switch carried thereby and adapted to control the electric circuit and a projecting arm on the switchin the path or" movementoi the--first-named lever, said projecti-on adapted to openand close the switch pair of supporting -when engaged and released by the firstlug and at the ther'end to the pivotally mounted lever at apoint adjacent the pivot se as to transmit a rocking movement of the lever during the expanding action of the container, a second pivotally mounted lever, a switch carried therebyand adapted to con trol the electric circuit and means on the switch disposed in the path of movement or? the first-named lever, said means adapted to open and close the switch when engaged or released by the first-named l'everand means whereby the position of the switch supporting lever may be changed.-

6. A device of the character described comprising a container constructed of an expansible material, a pair of supporting members secured to the container at points 0 posite each other, a lever pivotally mounted on one of said lugs, a rod of non-expansible materialsecured at one end to the opposite lug and at the other end to the pivotally mounted lever at a point adjacent the pivot so as to transmit a rocking movement of the lever during the expanding action of the container, a secondpivotally mounted lever, a switch carried thereby and adapted to control the electric circuit and means on the switch disposed in the path of movement of the first-named lever, said means adapted to 3 open and close the switch .when

engaged or released by the first-named lever and means whereby the position of the switch supporting lever may be changed and means permitting adjustment of the position of the lever upon which the switch is mounted.

OREN G. MYERS. 

